function ventana(id, width, height, modal, position) {
    $("#" + id).dialog({
        autoOpen: false,
        modal: modal,
        position: position,
        width: width,
        height: height,
        show: {
            effect: "drop",
            duration: 500
        },
        buttons: {
            "Cancel": function() {
                $(this).dialog("close");
            }
        }
    });
}